1. Field of the Invention
This invention relates to the preparation of an epoxide during the simultaneous oxidation of an aldehyde to the corresponding carboxylic acid. More particularly, this invention relates to the preparation of isobutylene oxide and isobutyric acid from isobutylene and isobutyraldehyde, respectively, by a co-oxidation process conducted in the presence of oxygen and in the presence of a homogeneous catalyst which is a soluble cobalt salt.
2. Prior Art
The preparation of ethylene oxide and propylene oxide by direct oxidation of the corresponding olefin in vapor phase in the presence of silver catalysts is known. Cooxidation processes are also well known in the art.
U.S. Pat. No. 3,265,716 discloses a process for the non-catalytic epoxidation of olefins such as cyclododecatrienc, dicyclopentadiene, methyl-2-heptene, butene-2, octene-1, cyclooctene, with a secondary aliphatic aldehyde such as isobutyraldehyde, which is converted to the corresponding acid.
U.S. Pat. No. 4,256,650 discloses a process for preparing propylene oxide and acetic acid by oxidation of propylene and acetaldehyde in liquid phase at a temperature of from 70.degree. to 100.degree. C. under a pressure of 40 to 50 atm. and in the presence of a boride catalyst.
U.S. Pat. No. 3,716,562 discloses a liquid phase oxidation process in which in the first stage oxygen is reacted with an olefin and an aldehyde in the presence of an inert diluent while in the second stage the reaction is continued in the presence of a molybdenum catalyst and without oxygen addition.
U.S. Pat. No. 3,347,763 discloses a process for preparing an olefin oxide and a carboxylic acid in which a liquid mixture of an aldehyde and an olefinic compound containing at least four carbon atoms and having the double bond in a non-terminal position is contacted with oxygen at a temperature of 30.degree. to 150.degree. C. Catalysts such as copper, manganese, nickel or cobalt salts may also be used in this process.
U.S. Pat. No. 4,483,998 teaches a co-oxidation process for simultaneously producing an epoxide and a carboxylic acid in which an olefin and an aldehyde are contacted with oxygen in the presence of a catalyst containing copper, boron and silver.
U.S. Pat. No. 4,046,783 teaches a liquid phase process in which an olefin is converted to the corresponding oxirane by contacting the olefin with molecular oxygen in the presence of a suitable solvent and in the presence of a molybdenum-containing catalyst material.
U.S. Pat. No. 2,316,604 discloses a process for the controlled oxidation of normally liquid olefinic materials with molecular oxygen in the presence of a solvent which can be an organic acid and in the presence of catalyst such as cobalt acetate, cobalt permaganate, copper acetate, etc.
U.S. Pat. No. 3,658,896 discloses a process for the oxidation of an olefinic hydrocarbon which utilizes a catalytic system consisting of a minor amount of a ruthenium compound and a major amount of a peracid.
U.S. Pat. No. 3,557,169 teaches a process for preparing carboxylic acids in which alpha olefins are dimerized and the dimerized materials are then oxidized with molecular oxygen in the presence of a catalyst such as cobalt bromide.
U.S. Pat. No. 3,407,221 discloses a process for oxidizing olefins to carboxylic acids by intimately contacting the olefin in liquid phase with oxygen in the presence of a cerium salt-nitric acid mixture as catalyst.
U.S. Pat. No. 3,414,594 teaches a process for preparing carboxylic acids and ketones by oxidizing olefins in a lower alkanol reaction medium and in a second step, oxidizing the ozonized olefin with molecular oxygen in the presence of an aqueous mineral acid. The second step reaction can also be conducted, if desired, in the presence of a cobalt salt catalyst.
U.S. Pat. No. 3,173,933 discloses a process for preparing carbonyl containing alkyl compounds in which alkyl compounds are reacted with oxygen in the presence of a catalyst soluble in the reaction mixture and consisting essentially of cobalt, bromine and a carboxylic acid.
U.S. Pat. No. 3,076,842 teaches a process by which an alkene-1, such as 1-octene, is oxidized with molecular oxygen to form an aliphatic, monocarboxylic acid product. The reaction is conducted at a temperature of about 50.degree. to 200.degree. C. and in the presence of a catalyst system comprising bromine and a heavy metal oxidation catalyst such as cobalt, nickel, iron supplied in elemental form, as the oxide or hydroxide or as a salt of the metal.
U.S. Pat. No. 2,437,648 discloses a process for the catalytic oxidation of unsaturated organic compounds such as olefins to yield products such as glycols, aldehydes, ketones and organic acids. The reaction is conducted in the presence of an inert, organic solvent, hydrogen peroxide and a small amount of a catalytically active oxide of a metal such as osmium, ruthenium, vanadium, etc.
U.S. Pat. No. 4,220,800 teaches a process for the conversion of olefinic carbon-carbon double bonds to vicinal diester groups by oxidation of the olefin compound which can be, for example, propylene, in the presence of a boron-containing catalyst and a carboxylic acid, carboxylic acid anhydride or mixtures thereof.
U.S. Pat. No. 4,098,817 discloses a process in which cycloaliphatic compounds are reacted in an organic ester solvent with molecular oxygen in the presence of a catalytic amount of, for example, cobalt acetylacetonate to form dibasic acids.